﻿using System;
using System.Collections.Generic;
using System.Text;

namespace HB.Expand.CRC
{
    /// <summary>
    /// MAXIM
    /// </summary>
    internal class CRC8MAXIM
    {
        /// <summary> 
        /// CRC8位校验表 
        /// </summary> 
        static byte[] CRC8Table = new byte[] {
        0,94,188,226,97,63,221,131,194,156,126,32,163,253,31,65,
        157,195,33,127,252,162,64,30, 95,1,227,189,62,96,130,220,
        35,125,159,193,66,28,254,160,225,191,93,3,128,222,60,98,
        190,224,2,92,223,129,99,61,124,34,192,158,29,67,161,255,
        70,24,250,164,39,121,155,197,132,218,56,102,229,187,89,7,
        219,133,103,57,186,228,6,88,25,71,165,251,120,38,196,154,
        101,59,217,135,4,90,184,230,167,249,27,69,198,152,122,36,
        248,166,68,26,153,199,37,123,58,100,134,216,91,5,231,185,
        140,210,48,110,237,179,81,15,78,16,242,172,47,113,147,205,
        17,79,173,243,112,46,204,146,211,141,111,49,178,236,14,80,
        175,241,19,77,206,144,114,44,109,51,209,143,12,82,176,238,
        50,108,142,208,83,13,239,177,240,174,76,18,145,207,45,115,
        202,148,118,40,171,245,23,73,8,86,180,234,105,55,213,139,
        87,9,235,181,54,104,138,212,149,203, 41,119,244,170,72,22,
        233,183,85,11,136,214,52,106,43,117,151,201,74,20,246,168,
        116,42,200,150,21,75,169,247,182,232,10,84,215,137,107,53 };

        public static byte CRC(byte[] buffer)
        {
            return CRC(buffer, 0, buffer.Length);
        }

        public static byte CRC(byte[] buffer, int off, int len)
        {
            byte crc = 0;
            if (buffer == null)
            {
                throw new ArgumentNullException("buffer");
            }
            if (off < 0 || len < 0 || off + len > buffer.Length)
            {
                throw new ArgumentOutOfRangeException();
            }

            for (int i = off; i < off+len; i++)
            {
                crc = CRC8Table[crc ^ buffer[i]];
            }
            return crc;
        }
    }
}
